That conclusion is also arguably supported by the history of the Mobility Allowance Regulations 1975 before their replacement by the Disability Living Allowance Regulations 1991 (discussed in paragraphs 33 to 38 above). However, in construing regulation 12(1)(a) regard may be had to the fact that it was made in order to set out the circumstances in which a person is to be taken to “suffer from physical disablement such that…”.

50.Turning to the substance of regulation 12, the history of the provisions again becomes relevant. The original form of the predecessor of regulation 12(1)(a) (i.e. prior to its amendment in 1979: see paragraph 27 above) qualified the then equivalent of section 73(1)(a) in only three respects. First, it used the phrase “his physical condition as a whole is such that” but only in the course of defining when a claimant was to be treated as unable or virtually unable to walk. It did not expressly touch the test for physical disablement. Second, it added the requirement that, in determining ability to walk, one should ignore circumstances peculiar to the claimant, such as place of residence. Third, it provided that a claimant should be regarded as unable or virtually unable to walk if the exertion required to walk would constitute a danger to his life or would be likely to lead to a serious deterioration in his health.

51.With regard to the first qualification, the regulation could simply have remained silent or have repeated the expression “suffering from physical disablement such that” used in the statute, but instead it used different wording from that in the primary legislation (then section 37A of the Social Security Act 1975). However, it is far from clear in what way, if at all, the meaning was intended to be different. The 1979 amendment raised additional issues (discussed in paragraphs 33 to 38 above).

52.The phrase “physical condition as a whole” in regulation 12(1)(a) is in our view ambiguous. Like the phrase “physical disablement”, it could be interpreted either as referring to the cause of the disablement (i.e. it has to be shown that there is something wrong with the claimant’s physical condition) or as referring to the functional ability that is impaired (i.e. the physical ability to make progress by putting one foot in front of the other). The background to the 1979 amendments (see paragraphs 28 to 38 above) tends towards the latter interpretation, but in our view far from decisively.

D.Significance of the absence of reference to mental disablement or condition

53.Mr Maurici submitted (and Mr Kolinsky accepted) that the difference in wording between section 73(1)(a) and regulation 12(1)(a) (which contain no reference to mental disablement or to the claimant’s mental condition) on the one hand, and section 72(1) and section 73(1)(d) (which use the words “so severely physically or mentally disabled”) on the other, must have some significance. Whereas the type of disability covered by the latter is unlimited, the statutory provisions intend some limit on the types of disability that will give entitlement to higher rate mobility component.

54.We remind ourselves that, as a matter of history (see paragraphs 23 to 26 above), when mobility allowance (i.e. the predecessor of section 73(1)(a)) was first introduced in 1975, attendance allowance (with the wording “so severely disabled physically or mentally that …..”) had been in existence for some 5 years. Mobility allowance was introduced by introducing section 37A into the Social Security Act 1975, attendance allowance being by then in section 35. Further, the contrast between what is now section 73(1)(a) and what is now section 73(1)(d) did not then exist, because lower rate mobility component was not introduced until the creation of DLA in 1992. Further, while attendance allowance had